The wumpus-core package

Wumpus is a low-level library for generating static 2D vector
pictures, its salient feature is portability due to no FFI
dependencies. It can generate PostScript (EPS) files and SVG
files. The generated PostScript code is plain [1] and reasonably
efficient as the use of stack operations, i.e gsave and
grestore, is minimized.

Pictures in Wumpus are made from paths and text labels.
Paths themselves are made from points. The usual affine
transformations (rotations, scaling, translations) can be
applied to Pictures. Unlike PostScript there is no
notion of a current point, Wumpus builds pictures in a
coordinate-free style.

GENERAL DRAWBACKS...

For actually drawing pictures, diagrams, etc. Wumpus is very
low level. There is a supplemantary package wumpus-basic
available that helps create certain types of diagram, but it is
experimental - functionality is added and dropped between
releases.

Some of the design decisions made for Wumpus-core are not
sophisticated (e.g. how attributes like colour are handled,
and how the bounding boxes of text labels are calculated), so
Wumpus might be limited compared to other systems. However,
the design permits a fairly simple implementation, which is a
priority.

[1] Because the output is simple, straight-line PostScript
code, it is possible to use GraphicsMagick or a similar tool
to convert EPS files generated by Wumpus to many other formats
(bitmaps).

Changelog:

0.33.0 to 0.34.0:

Clipping paths fixed. Previously they did not work for SVG or
PostScript.

picOver fixed. Drawing order was changed in version 0.33.0,
but picOver was not updated accordingly (so it actually
started drawing pictures under). It now works correctly.

The lexer for escape characters embedded in label strings has
been rewritten. It now supports octal and hexadecimal codes.

0.32.0 to 0.33.0:

Major change - reworked support for text encoding. Encoding
maps are now linked with fonts - it was spotted that the
Symbol font does not use the Latin1 names. The TextEncoder
data type has been changed and there is a new FontEncoder
data type. There are also new modules for the Symbol Font
encoder table and for the Default Encoder which
accommodates both Latin1 and the Symbol font. This has also
mandated changes to the FontFace data type.

Major change - the printing order has been changed. The first
element in a frame of Prims is draw first. This means it
appears first in the output file (this makes sense) - it also
means it is at the back in the Z-Order. This latter point
might not be so intuitive, but changing the printing order at
least makes Wumpus-Core match SVG and PostScript.

Changed the visiblity of the new colours (yellow, cyan,
magenta) to be hidden at the top level. They can be exposed
by importing Wumpus.Core.Colour.